Simon Peyton Jones pushed to branch wip/substitution-via-mapper at Glasgow Haskell Compiler / GHC Commits: 430967ab by Duncan Coutts at 2026-09-09T11:07:01+01:00 Reorder cmm decls in HeapStackCheck for a better logical grouping And put more section headers in to deliniate the groups. We're about to add more here, so better to organise it first. - - - - - 344080fd by Duncan Coutts at 2026-09-09T11:07:01+01:00 Add raisePrimIOException and add it to RTS<->ghc-internal API The raisePrimIOException is a new helper function that I/O primops will use to help them report I/O errors. This is implemented in Haskell (since that's a lot easier), but has a calling convention that is easy(ish) to use from Cmm in the I/O primops. So we add it to the RTS API struct, and since we'll use it from Cmm we also need a field accessor macro for cmm (in deriveConstants). See the Note about how we cannot have nice things due to async exceptions and thunks preventing us from using catch. - - - - - cfdb3399 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Add new blocking functions for I/O primops See the Note [Thread blocking for new I/O primops], and the Note [Calling convention for raisePrimIOException]. The point is, it will allow us to report synchronous exceptions from I/O primops, and do so much more flexibly. Previously the I/O managers could only report async exceptions and only nullary exceptions. This was OK historically, but no good as we add more I/O managers and expand the range of I/O operations we support. - - - - - f09c09d8 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Change the encoding of results from the I/O manager to I/O primops Previously we just had async continue or heap overflow. We now extend what we can report with synchronous success, and synchronous failure with an errno. See Note [Encoding of result of I/O manager operations] We don't use these two new cases yet, but we will. In particular an epoll I/O manager needs to be able to report synchronous success or failure for waitRead#/waitWrite#. - - - - - 30f074d9 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Switch waitRead/Write# to use new blocking return frames and update the I/O managers to set the result before resuming the blocked threads. This makes it possible for I/O managers to report synchronous exceptions from the I/O primops, but that will be done in a subsequent commit. - - - - - a8786ced by Duncan Coutts at 2026-09-09T11:07:01+01:00 Switch Poll and Select I/O managers to report sync exceptions rather than using raiseAsync with blockedOnBadFD_closure. This uses the new mechanism in the blocking frame return code to report synchronous exceptions. - - - - - 7a9df79a by Duncan Coutts at 2026-09-09T11:07:01+01:00 Remove now-unused blockedOnBadFD It was previously thrown by the select and poll I/O managers, but now they use raisePrimIOException (with an EBADF errno). - - - - - 6b0424e3 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Improve the docs for delay# waitRead# and waitWrite# Document that the waitRead/Write# can throw exceptions (this was true before too), and that all of them are async exception cancellation points. - - - - - afeb2c30 by Duncan Coutts at 2026-09-09T20:08:58-04:00 Enable printf warnings for trace functions and fix resulting warnings Most of the existing printf-style functions are annotated with attributes to enable gcc/clang warnings for the printf format string, but several trace functions in Trace.h were missing this annotation. Enable them, and fix the resulting warnings. - - - - - 9a442c93 by Alan Zimmerman at 2026-09-09T20:09:36-04:00 EPA: Exact print ConDeclGADT without custom enterAnn !16321 brought in explicit capture of parens in a ConDeclGADT. The ExactPrint update introduced a modification of the fundamental function in exact printing, `enterAnn`, by splitting it into a version allowing injection of functionality normally handled by the ExactPrint class methods. This commit refactors that code, to restore the prior `enterAnn` version, by following the convention in ExactPrint of introducing a helper data structure with its own `ExactPrint` instance to achieve the same effect. - - - - - 2168462f by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Try using TyCoMapper for substitutions - - - - - d4ee89b1 by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Implement substitution via TyCoMapper This is a significant bit of refactoring. The dependencies look like this, where each module depends on one above Defines Needs --------------------------------------------------- GHC.Core.TyCo.Rep Type, Coercion TyCoFolder GHC.Core.TyCo.FVs Free-var finders TyCoFolder GHC.Core.TyCo.Make Lots of mkX functions Free vars TyCoMapper GHC.Core.TyCo.Subst Substitution TyCoMapper, mkX functions GHC.Core.Type coreView, typeKind Substitution coercionKind GHC.Core.TyCo.Compare Comparison coreView Some `mkX` functions (such as `mkLRCo`, `mkInstCo`, `mkCastTy`) use substitution, and so are defined in GHC.Core.Type via a hs-boot import. - - - - - 9d88c7ba by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Make substitution strict It's nice that it is so easy to do so - - - - - 98f18698 by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Wibbles - - - - - dd2e2a2e by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Wibbles - - - - - 9bd8afe1 by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Wibble imports - - - - - b4812d8b by Simon Peyton Jones at 2026-09-10T17:31:49+01:00 Wibbles - - - - - 71 changed files: - compiler/GHC/Builtin/WiredIn/Prim.hs - compiler/GHC/Builtin/primops.txt.pp - compiler/GHC/Core/Coercion.hs - compiler/GHC/Core/Coercion.hs-boot - compiler/GHC/Core/Reduction.hs - compiler/GHC/Core/Seq.hs - compiler/GHC/Core/TyCo/FVs.hs - + compiler/GHC/Core/TyCo/Make.hs - + compiler/GHC/Core/TyCo/Make.hs-boot - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/TyCo/Rep.hs-boot - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/Type.hs - compiler/GHC/Core/Type.hs-boot - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Iface/Syntax.hs - compiler/GHC/Stg/EnforceEpt/TagSig.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Tc/Zonk/TcType.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/Types/Arity.hs - compiler/GHC/Types/Basic.hs - compiler/GHC/Types/Cpr.hs - compiler/GHC/Types/Demand.hs - compiler/GHC/Types/Name/Env.hs - compiler/GHC/Types/Name/Occurrence.hs - compiler/GHC/Types/Unique/FM.hs - compiler/GHC/Types/Unique/Map.hs - compiler/GHC/Types/Unique/Set.hs - compiler/GHC/Types/Var/Set.hs - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - + compiler/GHC/Utils/StrictIdentity.hs - compiler/ghc.cabal.in - libraries/ghc-internal/include/RtsIfaceSymbols.h - libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs - libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs - rts/Capability.c - rts/HeapStackCheck.cmm - rts/IOManager.c - rts/IOManager.h - rts/IOManagerInternals.h - rts/Messages.c - rts/Prelude.h - rts/PrimOps.cmm - rts/Printer.c - rts/STM.c - rts/Schedule.c - rts/Sparks.c - rts/StableName.c - rts/ThreadPaused.c - rts/Threads.c - rts/Trace.h - rts/include/rts/RtsToHsIface.h - rts/include/stg/MiscClosures.h - rts/posix/Poll.c - rts/posix/Poll.h - rts/posix/Select.c - rts/posix/Timeout.c - rts/sm/Compact.c - rts/sm/GC.c - rts/sm/GCUtils.c - rts/sm/MBlock.c - rts/sm/NonMoving.c - rts/sm/NonMovingMark.c - rts/sm/Storage.c - rts/sm/Sweep.c - utils/check-exact/ExactPrint.hs - utils/deriveConstants/Main.hs The diff was not included because it is too large. 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